Ultimately, you want to set it wherever it makes you happy - like what you've done. The others are correct, though, regarding not having interaction between the two frequency filters. After setting the crossover on the receiver to 80 Hz and then setting the crossover on the sub to 200 Hz, did you calibrate the system levels (or run an auto set-up if your receiver has one)? That might be the key. The sub might be set at too high of an output. Another possibility is that your room is causing an increase in volume at the frequencies around that cut-off of 80 Hz, and your adjustment of the subwoofer filter is helping to tame that.
Just some thoughts.